Gas handling system and method for efficiently managing changes in gaseous conditions

ABSTRACT

A system and method is provided for efficiently managing the compression of gas depending on the operating conditions and operating mode of the compression system, wherein the system includes a booster compressor, a booster compressor bypass, a conduit connected to the booster compressor and the booster compressor bypass conduit, a means for selectively directing the flow of the gas based on current operating conditions, to the booster compressor bypass or the booster compressor and a baseline compressor connected to both the booster compressor and the booster compressor bypass conduit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority and benefit of U.S. patentapplication Ser. No. 62/155129 filed on Apr. 30, 2015, entitled A GASHANDLING SYSTEM AND METHOD FOR EFFICIENTLY MANAGING CHANGES IN GASEOUSCONDITIONS, the contents of which are hereby incorporated by reference.

FIELD OF TECHNOLOGY

The following relates to systems and methods for gas handling systems,and more specifically to liquefied natural gas (LNG) or liquefiedpetroleum gas (LPG) gas handling systems having a gas compression systemwith an increased operating efficiency and a methods for managingchanges in the environmental conditions of the gas handling system.

BACKGROUND

Liquefied natural gas (LNG) and liquefied petroleum gas (LPG) may beproduced by cooling natural gas or petroleum gas into a liquid stateusing cryogenic cooling techniques. By condensing the gas into a liquidat a cryogenic temperature, the LNG or LPG can be stored in tanks orreservoirs, maintained as a liquid and transported long distances to adesired final destination, where the LNG or LPG can be re-gasified,pressurized and used by equipment or vehicles that consume the gas.

In order to manage, use or transport the liquefied gases stored in thestorage tanks and reservoirs, the LNG or LPG may need to undergo one ormore compression steps in an effort to increase the LPG or LNG to anoperating pressure of the system employing the LNG or LPG. Currentcompression methods and systems are considered to be inefficient.Inefficient systems and methods rely on a single compressor to handlethe entire compression workload in order to compress the LNG or LPG to adesired pressure. Operating conditions of systems utilizing an LNG orLPG system are known to vary dramatically depending on the operationmodes being utilized by these complex LNG or LPG systems, at anyparticular moment. Under a system that utilizes a single compressor tohandle the management of the gases, a compressor must be installed thatis capable of handling the expected maximum input of LNG or LPG to thecompression system and compressing it to the maximum required pressure.If a compressor is employed that cannot handle all variable changes tothe operating condition that may occur, the single compressor may beoverwhelmed and unable to handle the most extreme changes in operatingconditions, and thus fail to operate sufficiently under all conditions.

In systems that rely on a single compressor to handle larger volumes ofLNG or LPG, the compressor may be very large in size and use more powerto operate than smaller compressors. Moreover, when a single compressoris the only available option for every operation mode of the system, thecompressor must function continuously without being able to enter a lowpower or energy saving state. The gaseous compression system can beparticularly energy inefficient to constantly run due to the oversized,overpowered compressor operating at all times, even during normaloperating conditions where a smaller, more energy efficient compressorwould suffice.

Thus, a need exists for a gas handling system and method that is able todynamically adjust the compressors being utilized based on the currentoperating conditions, reducing the overall operating energy requirementsof the compressors in the system and increasing the efficiency of theLNG or LPG compression.

BRIEF SUMMARY

A first aspect of this disclosure relates to a gas compression systemcomprising a booster compressor, a booster compressor bypass conduit, aconduit connected to the booster compressor and the booster compressorbypass conduit, wherein the conduit selectively directs the flow of gasbased on current operating conditions to the booster compressor bypassor the booster compressor and a baseline compressor connected to boththe booster compressor and the booster compressor bypass conduit.

A second aspect of the disclosure relates to a method for compressinggas comprising the steps of providing a booster compressor, providing abooster compressor bypass, selecting an operating mode from a firstoperating mode or a second operating mode, wherein the first operatingmode is directing the gas through the booster compressor bypass and thesecond operating mode directing the gas to the booster compressor,compressing the gas into a compressed gas, and for both modes providinga baseline compressor receiving the gas from either the boostercompressor bypass or the compressed gas from the booster compressor andcompressing, by the baseline compressor, the gas or the compressed gas.

The foregoing and other features of construction and operation will bemore readily understood and fully appreciated from the followingdetailed disclosure, taken in conjunction with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the embodiments will be described in detail, with reference tothe following figures, wherein like designations denote like members,wherein:

FIG. 1a depicts a schematic view of an embodiment of a gas compressionsystem;

FIG. 1b depicts a schematic view of an alternative embodiment of the gascompression system of FIG. 1 a;

FIG. 2 depicts a schematic view of another alternative embodiment of agas compression system;

FIG. 3 depicts a schematic view of yet another alternative embodiment ofa gas compression system;

FIG. 4 depicts an embodiment of a computing system of a gas compressionsystem; and

FIG. 5 depicts a schematic view of an alternative gas compression systemcomprising a plurality of booster compressors.

DETAILED DESCRIPTION

A detailed description of the hereinafter described embodiments of thedisclosed apparatus, method, and system are presented herein by way ofexemplification and not limitation with reference to the Figures.Although certain embodiments are shown and described in detail, itshould be understood that various changes and modifications may be madewithout departing from the scope of the appended claims. The scope ofthe present disclosure will in no way be limited to the number ofconstituting components, the materials thereof, the shapes thereof, therelative arrangement thereof, etc., and are disclosed simply as anexample of embodiments of the present disclosure.

As a preface to the detailed description, it should be noted that, asused in this specification and the appended claims, the singular forms“a”, “an” and “the” include plural referents, unless the context clearlydictates otherwise.

Referring to the drawings, the schematic of FIG. 1a describes acompression system 100 which may be implemented or integrated into asystem for managing, controlling, utilizing, transporting or deliveringgases, such as from LNG or LPG systems. The embodiments of thecompression systems described below and depicted in the figures of thisapplication may be applied to numerous different types of natural gas,LNG or LPG systems, including, but not limited to LNG or LPG carriers,including LNG/LPG carrier propulsion systems, reliquefaction systems andLPG or LNG send out systems, as well as an LNG/LPG plant's liquefactionor purification facilities. Embodiments of the compression systemsdescribed below may also be integrated into systems for other LPG or LNGvehicles having an engine powered using natural gas, petroleum gas, andfilling stations or facilities used to deliver the LNG or LPG to thecarriers, vehicles and consumers.

Referring to FIG. 1 a, embodiments of the compression system 100 mayreceive a stream of compressed or uncompressed natural gas or petroleumgas via a conduit 101. The conduit 101 may transport the stream ofnatural gas or petroleum gas from a source such as a reservoir orstorage tank. In some embodiments, the reservoir or storage tank may befilled with LNG or LPG. In other embodiments, the source of the gasesentering the compression system 100 may be entering the compressionsystem 100 from an upstream process or system that may have utilized theLNG or LPG prior to the arrival at the compression system 100, viaconduit 101. As the gas enters the compression system 100 throughconduit 101, the gas may reach a junction point 102, wherein the gas mayenter either the booster compressor 105 or the gas may enter a boostercompressor bypass 103. Gas entering the booster compressor bypass 103may avoid the booster compressor 105.

Embodiments of the compression system 100 may employ the use of abooster compressor bypass 103 in order to avoid the use of the boostercompressor 105 during certain operating conditions. For example, underoperating conditions wherein the gas entering the system 100 via conduit101 may be capable of being adequately compressed and managed by system100 without the assistance of the booster compressor 105, the boostercompressor 105 may be bypassed. Conditions that are capable of beingmanaged by system 100 without the implementation of the boostercompressor 105 or additional auxiliary equipment supplementing thecompression capabilities of the default compression system 100, may bereferred to as baseline conditions.

Embodiments of a baseline condition may be a user defined or systemdefined value, or range of values, relating to the environment of thecompression system 100, wherein the system may adequately operatewithout employing additional auxiliary equipment, such as the boostercompressor 105. Baseline conditions may vary depending on the setup ofthe compression system 100 embodiments and the overall capabilities ofthe equipment provided within the compression system. The overallcapabilities of each system embodiment may change depending on theconfiguration of the compression system and the equipment performing thefunctions of the compression system.

A user may configure the baseline conditions of the embodiments of thecompression systems disclosed differently, depending on theenvironmental conditions a compression system may be capable ofoperating under. Environmental conditions a user may take into accountwhen configuring the baseline conditions may include values or ranges ofvalues for variables including but not limited to the volume of gasentering the system 100, the temperature of the system, the temperatureof the gas, the operating time, a set interval of time, the energyconsumption of the default equipment within compression system and themaximum operating capacity of equipment under the baseline conditions.

Moreover, environmental conditions may be monitored and measured in thecompression system 100 using one or more sensors placed within thecompression system 100. For example, one or more pressure sensors,thermal sensors, or temperature sensors may be placed within theconduits of the compression system 100 to transmit the environmentalcondition data relating to the measurement of operating environment andconditions of the gases flowing through the system. In otherembodiments, one or more sensors may be equipped or integrated into thebaseline compressor 109, booster compressor 105, or heat exchangers 111,112 in order to identify that the system 100 is operating within thebaseline conditions. In some embodiments, the data received by thesensors within the compression system 100 may be transmitted to acomputing system such as control panel or kiosk being used, maintainedor observed by an operator or administrator of the compression system100.

FIG. 4 illustrates a computer system 490 used for receiving thetransmission of data and information relating to the environmentalconditions of the gas compression system and activating one or moreoperating modes, in accordance with embodiments of the presentdisclosure. The computer system 490 may comprise a processor 491, aninput device 492 coupled to the processor 491, an output device 493coupled to the processor 491, and memory devices 494 and 495 eachcoupled to the processor 491. The input device 492 may be, inter alia, akeyboard, a mouse, etc. The output device 493 may be, inter alia, aprinter, a plotter, a computer screen, a magnetic tape, a removable harddisk, a floppy disk, etc. The memory devices 494 and 495 may be, interalia, a hard disk, a floppy disk, a magnetic tape, an optical storagesuch as a compact disc (CD) or a digital video disc (DVD), a dynamicrandom access memory (DRAM), a read-only memory (ROM), etc. The memorydevice 495 may include a computer code 497 which may be a computerprogram that comprises computer-executable instructions. The computercode 497 includes software or program instructions that may record anddisplay environmental conditions inside the gas compression system andmay further selectively activate one or more of the operating modesdescribed in this disclosure in response to the environmental conditiondata provided to the computing system. The processor 491 executes thecomputer code 497. The memory device 494 includes input data 496. Theinput data 496 includes input required by the computer code 897. Theoutput device 493 displays output from the computer code 497. Either orboth memory devices 494 and 495 (or one or more additional memorydevices not shown in FIG. 4) may be used as a computer usable storagemedium (or program storage device) having a computer readable programembodied therein and/or having other data stored therein, wherein thecomputer readable program comprises the computer code 497. Generally, acomputer program product (or, alternatively, an article of manufacture)of the computer system 490 may comprise said computer usable storagemedium (or said program storage device).

While FIG. 4 depicts the computer system 490 as a particularconfiguration of hardware and software, any configuration of hardwareand software, as would be known to a person of ordinary skill in theart, may be utilized for the purposes stated supra in conjunction withthe particular computer system 490 of FIG. 4. For example, the memorydevices 494 and 495 may be portions of a single memory device ratherthan separate memory devices.

In some embodiments, rather than being stored and accessed from a harddrive, optical disc or other writeable, rewriteable, or removablehardware memory device 495, stored computer program code 497 may bestored on a static, nonremovable, read-only storage medium such as aRead-Only Memory (ROM) device, or may be accessed by processor 491directly from such a static, nonremovable, read-only medium. Similarly,in some embodiments, stored computer program code 497 may be stored ascomputer-readable firmware, or may be accessed by processor 491 directlyfrom such firmware, rather than from a more dynamic or removablehardware data-storage device 495, such as a hard drive or optical disc.

Embodiments of the compression system 100 may include a plurality ofoperating modes. This plurality of operating modes may vary depending onthe configurations of the equipment in the compression system. Inembodiments having more complex configurations, the number of operatingmodes may be greater than simpler or less complex systems. The pluralityof operating modes may also vary depending upon the changes orfluctuations in operating conditions experienced by the compressionsystem. For instance, a system that experiences a wider array ofoperating conditions during the operation of the compression system 100,may include more operating modes to select from when a particularoperating condition is present in the compression system. Likewiseembodiments of compression systems 100 that experience less variation inoperating conditions may be programmed with a more limited number ofoperating modes. In some embodiments, the computing system, controlpanel or kiosk receiving data from the sensors may automatically selectand activate one or more of the operating modes described below inresponse to the changes in environmental conditions recorded by one ormore of the sensors present in the gas compression system. Inalternative embodiments, a user or administrator of the gas compressionsystem may manually select of the operating modes described herein inresponse to the changes in the environmental conditions present in thegas compression system and transmitted to a computing system receivingand monitoring the environmental conditions recorded by one or moresensors.

In some embodiments, the default operating mode may be selected whenbaseline conditions are present within the system. Embodiments of thesystem 100 operating at baseline conditions may consider this defaultoperating mode to be its first operating mode. In the first operatingmode, the stream of compressed or uncompressed gas entering the system100 through conduit 101 may be selectively directed to continue throughthe bypass 103 and avoid the booster compressor 105. By avoiding thebooster compressor 105 in the first operating mode, the boostercompressor 105 may remain in a low power state or in an off state, or ifpreviously activated, the change from a second operating mode back tothe first operating mode may cause the compression system to perform thestep of switching the booster compressor from an activated state to alow power state. The avoidance of the booster compressor 105 underbaseline operating conditions may be useful for reducing the energyconsumption of the compression system 100. After exiting the bypass 103,the gas may enter conduit 107. The conduits in this application arelabelled separately for discussion and identification purposes, howeverin some embodiments the conduits 101, 103 and 107 may be a onecontinuous conduit passing through each of the components of the gascompression described herein and depicted in FIGS. 1a to 3.

The gas exiting conduit 103 and being transported along conduit 107 mayenter an inlet for baseline compressor 109. A baseline compressor 109may be any compressor operational in the compression system 100 underbaseline conditions. The baseline compressor 109 may be the compressorhandling the compression and discharge of gas entering and exiting thesystem 100 without further assistance from auxiliary equipment underbaseline conditions. In some embodiments, the baseline compressor may bereferred to as a low duty compressor. The low duty compressor may be asingle stage or a multi-stage compressor. The type of low dutycompressor present in the compression system may depend on the overallsystem the compression system 100 is integrated into. For example, alow-duty compressor may have one to four stages or more. For instance,in an embodiment using a steam turbine propulsion system a 1-stage lowduty compressor may be present, whereas a dual fuel diesel-electric(DFDE) propulsion system, such as those used for LNG carriers, the lowduty compressor may be a 2-stage or 4-stage compressor.

Referring back to FIG. 1 a, the gas entering the inlet of baselinecompressor 109 may undergo a pre-selected or predetermined amountcompression to reach the requisite or desired pressure requirements of aLNG,LPG or any other system that the compression system 100 is a partof. Once the gas inside the baseline compressor has reached the propercompression levels, the compressed gas in conduit 110 may be dischargedfrom the compression system 100 and further transported to the desireddestination, machinery, engine or equipment for further use or storagedownstream from the compression system 100. In addition, the compressedgas in conduit 110 may exit an outlet and enter an inlet of anothercompressor for further compression in a compression system.

Embodiments of a baseline compressor 109 may be any type of compressorutilized within LNG,LPG or other gas-utilizing systems for the purposesof compression. Examples of compressors used may include dynamiccompressors such as centrifugal or axial compressors. Other compressorsthat may be used in the compression system 100 may include reciprocal orrotary compressors. Types of reciprocating compressors may include butare not limited to diaphragm, double acting or single actingcompressors, while types of rotary compressors may include lobe,helical-screw, liquid ring, scroll or sliding vane compressors.

Embodiments of system 100 may further include a plurality of one or moreadditional operating modes beyond the first operating mode. Eachdifferent operating mode may be separately initiated when one or morevariables describing the environmental conditions of the system's 100baseline conditions extends above or below the value, or range ofvalues, programmed or set by the user or system. Each of the differentoperating modes may be referred to by a name or number. For example,each subsequent operating mode may be referred to as a second, third,fourth, fifth, sixth, etc. or by a descriptive name, such as the boosteroperating mode, low power operating mode, supplementary operating mode,liquefaction operating mode, or any other descriptive title that mayindicate the purpose of the operating mode being engaged by thecompression system.

There may be no limit to the number of operating modes that may beprogrammed, selectable or activated by the compression system 100 inresponse to different variations in the baseline conditions orenvironmental conditions present in the compression system. Fluctuationsin baseline operating conditions may occur frequently, infrequently orat set intervals based on the type of LNG, LPG or other gaseous systemthe compression system 100 is connected to. The additional systems ofthe LNG, LPG or other gaseous systems may continuously activate ordeactivate and the effects of those additional systems may cause changesin the environmental conditions present in the compression system 100.In response to the changes, the compression system 100 may respond bytriggering, activating, initiating or executing one or more of thedifferent operating modes programmed to become activated in response tothe environmental changes of the compression system.

Under circumstances where the environmental conditions inside thecompression system 100 may cause another operating mode to activate,additional equipment connected to the compression system 100 mayactivate in a manner selected, designated or programmed by a user or bythe system itself, either manually or automatically. For instance, insome embodiments, a second or subsequent operating mode may activate thebooster compressor 105 to assist the baseline compressor 109 with thecompression of the gases introduced into the system 100. A boostercompressor 105 may refer to any type of compressor which may provide atemporary increase to the pressure in the gas compression system andadditional compression beyond the capabilities of compressors operatingunder baseline conditions, to meet a target pressure for compressed gasexiting the gas compression system. Embodiments of the boostercompressor discharge into the inlet or suction line of anothercompressor. Embodiments of the booster compressor 105 in the system 100may discharge the gases compressed by the booster compressor 105 intothe inlet of the baseline compressor 109 for further compression via theintermediate conduit 107.

In one or more embodiments of system 100, where an operating mode hasactivated, for example in response to an environmental condition presentin the gas compression system 100 is outside of a pre-programmed orpredetermined value or range of values, the gases arriving to the system100 via conduit 101 may be selectively directed to travel to the boostercompressor 105, instead of the booster compressor bypass 103 used in thefirst operating mode. As the gases enter the booster compressor 105,they may be compressed to an intermediate pressure that may bemanageable by the baseline compressor 109. This preliminary compressionstep may assist the baseline compressor both by reducing a volume of gasgoing to the baseline compressor 109 and by decreasing the overallamount of compression to be performed by the baseline compressor, inorder to meet the pressure requirements of the discharged compressed gasin conduit 110. Subsequently, the baseline compressor 109 receiving theintermediate compressed gas from the booster compressor 105 discharge,may further compress the gases to achieve the compression system's 100target level of compression in conduit 110.

For example, under the baseline conditions, the first operating mode ofsystem 100 may remain active when the system operates under a specifiedtemperature or range of temperatures. When the temperature of the system100 fluctuates above or below the temperature range settings programmedfor the baseline conditions, a second operating mode may be initiated oractivated by the gas compression system. In this example, as thetemperature rises beyond the baseline conditions, the volume of the gasentering the compression system 100 may increase to a level that isbeyond the capabilities of the baseline compressor 109 to properlycompress on it own in order to meet the required discharge pressure inconduit 110 of the LNG, LPG or other gas system. In some embodiments,the second operating mode may initiate a second compressor, such as thebooster compressor 105 to compensate for the rise in the volume of gas,due to the temperature fluctuation beyond the baseline conditions. Inthis embodiment, once the booster compressor 105 is activated, thebooster compressor 105 may initially compress the gases entering thecompression system to an intermediate pressure that is manageable by thebaseline compressor. In some embodiments, the compressed gasesdischarged from the booster compressor 105, may have a pressure that isgreater than the pressure of the gases entering the compression system100 via conduit 101, but less than the final discharge pressure 110. Thebaseline compressor receiving the compressed gases discharged from thebooster compressor 105 may further compress the discharged gasses fromthe booster compressor to further raise the pressure to a pressurerequired for the discharged gases in conduit 110 of the gas handlingsystem.

Embodiments of the compression system 100 may dynamically respond tochanges in the environmental conditions present within the compressionsystem 100 at any point during the operation thereof. As describedabove, embodiments of the compression system 100 may enter one or moredifferent operating modes when variables defining the environmentalconditions shift outside of the values set or range of values set as thebaseline conditions. This dynamic response to changes in environmentalconditions of the compression system 100 may occur by both selectivelyactivating a second or subsequent operating mode as well as thesubsequent return to the first operating mode when baseline conditionsare met again.

Using the temperature example above, embodiments of LNG or LPG systemsmay include a re-liquefaction system which may activate and deactivateas it is needed. The activation and deactivation of the re-liquefactionsystem at one section of the LNG or LPG system may actually cause a riseand fall in environmental temperature of the gases entering compressionsystem 100 through conduit 101. In some embodiments of an LNG or LPGsystem, activation of a re-liquefaction system may cause a rise intemperature of the gases entering the compression system 100 and therise in temperatures may exceed the baseline conditions of the firstoperating mode. In response to the environmental conditions containing atemperature above the range of acceptable baseline temperatures,embodiments of the system 100 may dynamically activate a secondoperating mode to assist the compression system. The second operationmode may utilize both the booster compressor 105 and the baselinecompressor 109 together in tandem to achieve a requisite dischargepressure in conduit 110 of the gas handling system incorporatingcompression system 100.

Subsequently, the LNG, LPG or other gas handling system may deactivateits re-liquefaction system connected to the downstream compressionsystem. The deactivation of the re-liquefaction system may cause thetemperature of the gases reaching the compression system 100 locateddownstream from the reliquefaction system to decrease back to within thebaseline conditions. In response to the return of the gas temperaturebeing within an acceptable range of the preset or pre-programmedbaseline conditions, the compression system 100 may cease operating inthe second operating mode and return to the first operating mode whichmay utilize the booster compressor bypass 103 to circumvent the unneededbooster compressor 105.

Embodiments of the compression system 100 may vary depending upon theequipment employed as part of the compression system. For example, asystem 100 may include varying number of valves 124, 125, 126, 128,switches or gates 121, 123 and heat exchangers or intercoolers 111, 112.The type, configuration, location, and/or number of valves, switches,gates, heat exchangers or intercoolers integrated into the compressionsystem 100 may depend on the purpose of the LNG, LPG or other gashandling systems that the embodiments of the compression system 100 areconnected with. Moreover, the size, stages and energy consumption of thebooster compressor 105 or baseline compressor 109 may vary and thus theamount of compressors needed, and the amount of cooling provided by theplurality of heat exchangers or intercoolers to these compressors 105,109 may also vary as needed to maintain proper operating conditions orselected operating modes.

In further embodiments, an operating mode may include the operation ofthe booster compressor 105 alone, while the baseline compressor(s) maybe turned off. For example, under circumstances where the environmentalconditions inside the compression system may cause this operating modeto activate, gases arriving to the system 100 via conduit 101 may travelto the booster compressor 105, instead of utilizing the boostercompressor bypass 103 used in the first or other operating mode. As thegases enter the booster compressor 105, the gases may be compressed to apressure suitable for discharge at a target level of compressionproducing a compressed gas in conduit 110. In such an embodiment whereinthe gases bypass the low duty baseline compressor 109, the gases mayexit the booster compressor 105 via conduit 107, and bypass the baselinecompressor(s) via a baseline compressor bypass configured to bypass thebaseline compressor 109 (which may be turned off) and reach an outlet ofthe compression system discharging compressed gas 110.

In an alternative embodiment of a compression system 200, as shown inFIG. 1 b, a compression system 200 may further include a recycling loop201 which may be connected to an inlet and a discharge of the boostercompressor 105. In some embodiments of compression system 200, a portionof the gas entering the compression system 200 via conduit 101 may enterthe booster compressor 105 instead of the bypass 103 at a first junction102. In an effort to limit the effects of the booster compression loopwhen the first operating mode is active, the compressed gas exiting thedischarge of the booster compressor 105 may be diverted into the recycleloop 201 instead of continuing along to conduit 107. As the gas, such asan intermediate compressed gas exits the discharge of the boostercompressor, the recycling loop 201 may transfer the gas exiting thedischarge of the booster compressor back to an inlet of the boostercompressor.

As shown in the exemplary embodiment of FIG. 1 b, the gases entering viaconduit 101 may be directed to either enter the booster compressor 105or the booster compressor bypass 103. As a portion of the gases enterthe booster compressor 105, the discharged gases may be prevented fromaccessing the conduit 107 by a control valve, such as the processcontrol valve 124 depicted in the figure. Because the compressed gasescannot pass beyond the control valve 124, the gas may be forced into therecycling loop 201 which cycles the intermediate compressed gas back tothe booster compressor 105. As the conduit transporting the gasesthrough the booster compressor becomes pressurized, additional gas maybe unable to enter the booster compressor 105 or recycling loop 201 andtherefore the gases entering the compression system 200 via conduit 101may be forced through the bypass 103 when system 200 is functioning inthe first operating mode.

The bypass 103 may also comprise a control valve 125 in someembodiments. When operating in the first operating mode under baselineconditions, this control valve 125 may remain open, allowing for thegasses to pass through the bypass 103 into the second conduit 107 andfurther into the inlet of the baseline compressor 109. However, in anembodiment of the compression system 200, wherein the operating mode mayhave switched from a first operating mode to a second operating mode,the control valve 125 present in the bypass 103 may close. Likewise, ascontrol valve 125 closes upon changing to the second operating mode, thecontrol valves 126 and 124, present in the booster compressor 105 loop,may open. In this embodiment, when the second operating mode isinitiated, control valve 126 will open, control valve 124 will open,then control valve 125 will close and direct the gas to the boostercompressor 105. The control valve 125 may partially or fully close tolimit or prevent the gas leaving booster compressor 105 from returningto the inlet of booster compressor 105. Thus, the gasses entering thecompression system 200 may be directed through the alternative routecomprising the booster compressor 105 discharging into the inlet orsuction line of baseline compressor 109 via conduit 107.

As the gas that was previously trapped in the recycling loop 201discharges from the booster compressor 105, the gas may now exit throughthe control valve 124 that opened when the second operating modeactivated. Instead of being caught in the recycling loop 201, the gasesmay now enter conduit 107 under the desired intermediate pressureprovided by the booster compressor 105 and may be properly pressurizedby the baseline compressor to the compressed discharge pressure inconduit 110. Furthermore, embodiments of the compression system 200 mayfurther comprise one or more valves or gates, such as check valve 121and 123, to prevent or hinder gas in conduit 107 from flowing backwardsin the system. A control valve, such as process control valve 124, maybe placed proximate, next to, or otherwise near check valve 123 to allowfor the booster compressor 105 to be isolated and started withoutaffecting the system 200. As shown in FIG. 1a and 1 b. the one way checkvalve 121 may prevent the gases travelling from the bypass conduit 103to the conduit 107 from travelling backwards into the bypass conduit.Likewise, check valve 123 may prevent gases exiting the boostercompressor into conduit 107 from flowing back into the boostercompressor loop or the recycling loop 201.

In the exemplary embodiments of the compression systems described hereinand pictured in FIGS. 1 a, 1 b, 2, and 3, the booster compressor 105 andthe baseline compressor 109 may be depicted as two or more physicallyseparate compressor units. However, in alternative embodiments, thebooster compressor 105 and the baseline compressor 109 may be a singlecompressor unit having multiple stages of compression, including abooster compressor section and a baseline compressor section. Similar tothe systems described above, the single, integrated compressor unit mayoperate in multiple stages depending on the environmental conditions ofthe compression system and be further programmed to have a plurality ofselectable operating modes, similar to the previous systems discussed.Likewise, embodiments of the integrated compression unit may alsocontain an open bypass when operating if the first operation mode whichmay prevent gas from entering the booster stage of the integratedcompressor, as well as a recycling loop for the booster stage in someembodiments. Moreover, much like the embodiments described above, theintegrated compressor unit may dynamically switch, engage or activatethe programmed operating modes to engage or disengage the boostercompression stages of the integrated compressor based on theenvironmental conditions and the pre-set baseline conditions or rangesof conditions.

Embodiments of the compression system 100, 200 are not limited tosystems having only a single booster compressor 105 and a singlebaseline compressor 109. In some embodiments of compression systems,there may be a plurality of baseline or booster compressors employed inthe system or a integrated baseline or booster compressor having aplurality of stages. As depicted in the embodiment of compression system300, the baseline compressor may comprise one or several stages ofcompression. As shown by the exemplary embodiment of FIG. 2, thebaseline compressor can be configured with a preset number of stagesneeded to reach the discharge in conduit 110 with the desired pressure.

In some embodiments, a plurality of baseline compressors 109, 309, 311,313 may be used for the purposes of decreasing the size of thecompressors or increasing energy efficiency over a system employing afewer number of larger or more powerful compressors. In alternativeembodiments, the system may employ multiple baseline compressors, wherefewer compressors may not be feasible or practical. The number ofbaseline compressors or number of stages a baseline compressor may havein the system 300 may vary depending on the requirements and the uses ofthe LNG, LPG or other gas system integrating the compression system 300.

In alternative embodiments of the compression system, a plurality ofbaseline compressors 109, 309, 311, 313 are not limited to only beingplaced in series with one another to increase the overall pressurizingcapabilities or efficiency of the compression system. In somealternative embodiments, a plurality of one or more baseline compressors109, 309, 311, 313 may be placed in parallel with a second plurality ofbaseline compressors 408, 409, 411, 413.

As depicted in FIG. 3, a gas entering via conduit 107 may either enterthe first plurality of baseline compressors 109, 309, 311, 313 and/orthe second plurality of parallel baseline compressors 408, 409, 411, 413via conduit 407. The gas entering the first plurality of baselinecompressors 109, 309, 311, 313 and second plurality of baselinecompressors 408, 409, 411, 413 may be compressed by one or more of thecompressors until the pressure of the gas entering the second pluralityof baseline compressors is discharged at the desired target pressure ateither the first discharge in conduit 110 or the second discharge inconduit 410. As depicted in the exemplary embodiment, the compressedgases in conduit 110 and conduit 410 may combine to form a single streamof gases in conduit 420 having a pressure at the requisite pressuredesired by the user and the gas system integrating or utilizing thecompression system 400. These combined gases in conduits 110, 410 thatflow into conduit 420 may then be transported to the next downstreamstep of the LPG, LNG or other gas system.

As the embodiments of the compression system integrated into the LNG,LPG or other gas systems becomes more complex or includes additionalequipment and arrangements, additional operation modes may be utilized.For example, the first operating mode under baseline conditions in thecompression system 400 may not utilize both the first plurality ofbaseline compressors 109, 309, 311, 313 and the second plurality ofbaseline compressors 408, 409, 411, 413 in some embodiments. Instead,operating modes may select one plurality of baseline compressors overthe other, or the system may dynamically increase the number of activecompressors in a set of each series of compressors as needed tocompensate for changes in environmental conditions and compression workload.

In alternative embodiments of the compression system 400, not all of thecompressor may be utilized at all times. In one instance, the firstoperating mode may only employ the first plurality of baselinecompressors 109, 309, 311, 313. In the second operating mode, the system400 may initiate the second plurality of baseline compressors when theenvironmental conditions of the system 400 reach a preset orpreprogrammed value or within a range of values or parameters definingone or more environmental conditions. Subsequently, in some embodiments,a third operating mode may be employed when a predetermined set ofenvironmental condition or variable values may be met, wherein thebooster compressor, the first plurality of compressors 109, 309, 311,313 and the second plurality of booster compressors 408, 409, 411, 413alone, or in combination of one another may be activated.

In yet another embodiment, a fourth operating mode may be activatedunder a different set of conditions that may not arise to activate thefirst, second or third operating mode. For example, in this alternativeembodiment, when the fourth operating mode is activated, the boostercompressor may be activated along with the first plurality of baselinecompressors. Alternatively in other embodiments, the operating mode mayactivate the baseline compressor and the second plurality of baselinecompressors. Moreover, in additional embodiments of the compressorsystems discussed above, the compressor system 500 may include aplurality of one or more booster compressors 105, 505 as shown in FIG.5. The booster compressors may be used simultaneously depending on theoperating mode activated, or the number of booster compressors engagedmay increase or decrease depending on the operating mode selected by theuser or as a result of the environmental conditions.

In addition to using the compressors in different operating modes, whenthere are compressors arranged in parallel, such as shown in FIG. 5, theplurality of one or more baseline compressor or the plurality of boostercompressors 105, 505 may be used to provide back-up in case one or morecompressors fail, is out of service for maintenance or otherwise notavailable. In some embodiments, the booster or baseline compressors mayalso be used alternately to balance the number of operating hours foreach of the compressors in a particular operating mode.

As shown in FIG. 5, some embodiments of system 500 may include a heatexchanger 511, a recycling loop 501 and a valve or gate 523 connectedvia a conduit to the baseline compressor 501. The components of theparallel booster compressor 501 pathway may operate in the same orsimilar manner booster compressor 105, heat exchanger 111, valve or gate123 and recycling loop 201. For example, whereas the heat exchanger 11receives compressed gas from booster compressor 105, which enters therecycling loop 201 unless the gate 123 is opened, the gas enteringbooster compressor 505 may pass through heat exchanger 511 and returnback to the booster compressor 505 via recycling loop 501 unless thevalve or gate 523 is in the open state.

Referring now to FIGS. 1a -5, embodiments of methods for compressing agas using the embodiments of the systems described above may include thesteps of providing one or more booster compressors, a booster compressorbypass and one or more baseline compressors. The embodiments of methodsmay include the step of receiving by a conduit a stream of gas, such asan uncompressed gas or compressed gas into a gas compression system. Insome methods, a step of measuring the environmental conditions withinthe conduit may be performed, for example through the use of sensorsplaced within the conduit. As previously described above, the gascompression system may have a pre-programmed value or range of values.Upon measuring the environmental conditions present in the conduit, thesensors may transmit environmental condition data to a computing systemcomparing the collected environmental conditions with the pre-programmedor pre-set environmental conditions.

In some embodiments of the method, after collecting and comparing thedata describing the environmental conditions of the gas compressionsystem, in some methods the gas compression system or a computing systemconnected thereto may further perform the step of selecting an preset orprogrammable operating mode.

The step of selecting the operating mode may include selecting anoperating mode from a plurality of operating modes. In some embodimentsthe step of selecting an operating mode may be performed automaticallybased on the values or range of values defining the operating conditionsand the environmental condition within the compression system itself. Inalternative embodiments, the step of selecting the operating mode may beperformed manually by the user of the compression system. For example auser may be selecting the operating mode at a remote or networkaccessible computing system electronically or remotely connected to thecompression system.

In an example of an exemplary embodiment, the step of selecting anoperating mode may be made by selecting a first operating mode or asecond operating. In some embodiments, when the first operating mode isselected, the compression system may proceed by directing the stream ofgas entering the system through a booster compressor bypass. Thedirecting of the gas may be performed by one or more valves provided bythe compression system and placed within the booster compressor bypassconduit and/or the booster compressor loop. Alternatively, the step ofselecting a second operating mode may proceed by directing the stream ofgas entering the compression system to the inlet of the boostercompressor, wherein the booster compressor is active and operational,compressing the incoming gas to an intermediate compressed gas,discharging the gas at an intermediate pressure and transporting theintermediate compressed gases to the baseline compressor downstream fromthe booster compressor for further compression.

Embodiments of the methods for further compressing a gas to a desiredfinal pressure may further include transporting the gas discharged fromthe booster compressor or the booster compressor bypass to one or morebaseline compressors receiving the gas through the baseline compressorinlet. In some embodiments, the baseline compressor may proceed bycompressing the gas received, pressurizing the gas to a predetermined orpre-requisite pressure and discharging the gas from one or more of thebaseline compressors in the system at the pressure desired by the userof the system.

In an alternative embodiment comprising one or more baseline compressorsrunning in parallel, receiving the gas from either the boostercompressor or the booster compressor bypass, the method may furtherinclude the step of combining the pressurized gas from the each of thebaseline compressors, after the step of discharging the gas from thebaseline compressors at the pre-set, or pre-requisite pressure.

The following software simulation examples are provided for illustrativepurposes. The simulations are intended to be non-limiting and areintended to further explain and assist in clarifying the benefits andenergy savings are realized when one or more of the elements of theembodiments described above are employed:

TABLE 1 Single Compressor System Operating Conditions 1 2 3 Gas Composi-Nitrogen - 7.41 Nitrogen - 7.41 Nitrogen - 7.41 tion (mol %) Methane -92.56 Methane - 92.56 Methane - 92.56 Ethane - 0.03 Ethane - 0.03Ethane - 0.03 Total 100 100 100 Molecular 16.93 16.93 16.93 weight MassFlow 6000 6000 6000 (kg/hr) Inlet Pressure 1.06 1.06 1.06 (barA) InletTempera- 20 −90 −110 ture (° C.) Discharge 17 17 17 Pressure (barA)Coupling 1246 1355 1571 Power (kW)

TABLE 2 Booster Compressor System Operating Conditions 1 2 3Configuration Booster Baseline Baseline only Baseline only Booster - OffBooster - Off Gas Composition (mol %) Nitrogen - 7.41 Nitrogen - 7.41Nitrogen - 7.41 Nitrogen - 7.41 Methane - 92.56 Methane - 92.56Methane - 92.56 Methane - 92.56 Ethane - 0.03 Ethane - 0.03 Ethane -0.03 Ethane - 0.03 Total 100 100 100 100 Molecular weight 16.93 16.9316.93 16.93 Mass Flow (kg/hr) 6000 6000 6000 6000 Inlet Pressure (barA)1.06 2.2 1.06 1.06 Inlet Temperature (° C.) 20 46 −90 −110 DischargePressure (barA) 2.35 17 17 17 Coupling Power (kW) 319 1056 1070 1053Total Coupling Power (kW) 1375 1070 1053 Coupling Power Differential+128.7 kW −285 kW −464 kW (Table 2 − Table 1)

As demonstrated by the simulation data presented above in Tables 1 and2, the booster compressor system offers a significant energy savingsover the single compressor system simulated in Table 1. By introducing adynamically activated and deactivated booster compressor that may onlybe needed to operate under more stressful conditions, the baselinecompressors of the booster compressor system simulated in Table 2 may besmaller, more energy efficient and include a lower number of stages thatthe compressors needed for the single compressor system provided in thesimulation of Table 1. The compressors in the single stage compressorsystem may be larger, more complex, have an increased number ofcompression stages and thus require more energy to operate because thesingle compressor system described in the simulation of Table 1 shouldbe designed in a manner that allows for the single compressor to handlenot only colder compressed gases at lower temperatures (such as −90° C.and −110° C.), but also warmer gases having an inlet temperature of 20°C. as shown in the example. With a wider range of operation, the singlecompressor system may require a higher overall coupling power, whereasbooster compressor system having the results of Table 2 may rely on thebooster compressor for the compression of warmer gases (such as the 20°C. example) to an intermediate pressure followed by final compressionwith the baseline compressor.

Although temperature conditions that selectively implement an operatingmode that utilizes both the booster compressor and the baseline may seean increase of coupling power to provide an adequate amount of overallcompression in some embodiments, as shown in Table 2, under an operatingmode that does not require the implementation of the booster compressor,a significant savings can be realized in the amount of coupling powerused. As shown in the table 2 above, by being able to use a more energyefficient baseline compressor, the booster compressor system of table 2was able to reduce coupling power for handling non-booster operatingmodes by 285 kW and 464 kW at temperatures of −90° C. and −110° C.respectively. A reduction in coupling power of the baseline compressorbetween 18 to 35%. However, depending of the configuration of theparticular embodiments as described above, it is anticipated thatsavings in coupling power of the compressors may be a reduction of35-50%, 50-65%, 65-85%, or 85-100%.

While this disclosure has been described in conjunction with thespecific embodiments outlined above, it is evident that manyalternatives, modifications and variations will be apparent to thoseskilled in the art. Accordingly, the preferred embodiments of thepresent disclosure as set forth above are intended to be illustrative,not limiting. Various changes may be made without departing from thespirit and scope of the invention, as required by the following claims.The claims provide the scope of the coverage of the invention and shouldnot be limited to the specific examples provided herein.

1. A gas compression system comprising: a booster compressor; a boostercompressor bypass; a conduit connected to the booster compressor and thebooster compressor bypass, wherein a stream of gas is selectivelydirected through the booster compressor based on a measurement of anenvironmental condition present in the gas compression system.
 2. Thegas compression system of claim 1, further comprising: a baselinecompressor connected to the conduit, the baseline compressor receives acompressed gas from the booster compressor if the measurement ofenvironmental condition is outside a value or range of values.
 3. Thegas compression system of claim 1, wherein the conduit further comprisesa sensor, wherein said sensor measures the environmental conditionswithin the conduit and transmits data of the environmental condition toa computing system.
 4. The gas compression system of claim 1, whereinthe sensor measures an environmental condition selected from the groupconsisting of a volume of gas, temperature of gas and the temperature ofthe gas compression system.
 5. The gas compression system of claim 1,further comprising a recycling loop connected to an inlet and adischarge of the booster compressor.
 6. The gas compression system ofclaim 5, wherein the recycling loop returns an intermediate compressedgas that exits the discharge back to the inlet of the boostercompressor.
 7. The system of claim 1, wherein the gas compression systemselectively directs the flow of gas to the booster compressor bypasswhen the measurement of the environmental condition present in the gascompression system is outside a value or range of values.
 8. The gascompression system of claim 7, wherein the booster compressor enters alow power state when the gas compression system selectively directs theflow of gas to the booster compressor bypass.
 9. The system of claim 2,comprising an integrated compressor unit incorporating the boostercompressor, the baseline compressor and the booster compressor bypassinto a single compressor unit having multiple stages, wherein thebooster compressor is a booster stage of an integrated compressor unit,and the booster compressor bypass is a bypass that prevents gas fromentering the booster stage.
 10. The system of claim 2, wherein thebaseline compressor is a plurality of baseline compressors connected toone another in a series configuration.
 11. The system of claim 10,wherein a second plurality of baseline compressors connected in a seriesconfiguration are connected to the conduit and are parallel to theplurality of baseline compressors.
 12. A method for compressing a gascomprising the steps of: receiving, by a conduit, a stream of gas;measuring an environmental condition present within the conduit;selecting an operating mode, from a first operating mode and a secondoperating mode as a function of the measuring step, wherein the firstoperating mode is selected when a measured value of the environmentalcondition is within a value or range of values and the second operatingmode is selected when the measured value of the environmental conditionis outside of the value or range of values; activating the secondoperating mode so that the stream of gas from the conduit is directed toa booster compressor connected to the conduit.
 13. The method of claim12, further comprising the steps of: compressing, by the boostercompressor, the gas to an intermediate compressed gas; transporting theintermediate compressed gas to a baseline compressor; and furthercompressing, by the baseline compressor, the intermediate compressed gasto a compressed gas.
 14. The method of claim 12, wherein the step ofmeasuring the environmental condition is performed by one or moresensors provided within the conduit.
 15. The method of claim 12, whereinthe environmental condition is the volume of the gas, temperature of thegas or temperature within the conduit, or the composition of the gaswithin the conduit.
 16. The method of claim 12, further comprising thesteps of: activating the first operating mode; directing the stream ofgas from the conduit to a booster compressor bypass connected to thebaseline compressor; and compressing, by the baseline compressor, thegas into the compressed gas.
 17. The method of claim 16, furthercomprising the steps of: transferring, upon activating the firstoperating mode, the intermediate compressed gas exiting a discharge ofthe booster compressor into a recycling loop connecting the discharge ofthe booster compressor and an inlet of the booster compressor;transferring the intermediate compressed gas from the recycling loop tothe inlet of the booster compressor.
 18. The method of claim 16, furthercomprising the step of: switching the booster compressor to a low powerstate.
 19. The method of claim 13, wherein the booster compressor andbaseline compressor are an integrated compressor unit, wherein thebooster compressor is a booster stage of the integrated compressor unit.20. The method of claim 13, wherein the further compressing step isperformed by a plurality of baseline compressors connected to theconduit in a series configuration.
 21. The method of claim 13, whereinthe further compressing step is performed by a first plurality ofbaseline compressors connected in a first series configuration, a secondplurality of baseline compressors connected in a second seriesconfiguration and said first plurality of baseline compressors are in aconfiguration parallel to the second plurality of baseline compressors.